1. Field of the Invention
The present invention relates to automated conveying systems for transporting biological and chemical specimens and the like, e.g., vials of blood, along a predetermined transport path, e.g., from a loading station to a work station for analysis or processing. More particularly, this invention relates to improvements in specimen carriers adapted to be transported by a conveyor system while supporting a specimen container in a generally upright orientation, and to methods and apparatus for identifying such carriers as they are transported. Another aspect of this invention relates to methods and apparatus for identifying such carriers.
2. Discussion of the Prior Art
Automated systems for analyzing various properties of biological and chemical specimens are well known. In certain automated blood analyzing systems, for example, a conveyor belt or the like serves to transport individual containers (e.g., vials or test tubes) of blood along a predetermined path, and blood analyzing or processing instruments positioned along such path operate to extract and process a blood sample from each container as and when presented to it. Such instruments may include, for example, one or more hematology instruments for performing red and white cell analyses on the sample, flow cytometers for identifying cell types through fluorescence measurements, coagulation instruments for measuring a blood sample""s coagulation time, and slide-making instruments for making blood smears on microscope slides for subsequent analysis. Such instruments often comprise a dedicated aspiration mechanism including an aspiration needle or probe which serves to puncture a seal on the specimen container and to aspirate a portion of the sample within. Typically, the aspiration needle is designed to move vertically as it enters and exits the specimen container. Thus, to facilitate sample aspiration, as well as to avoid any spillage of the sample during transport through the system, it is usually desirable to support the container in a vertically upright orientation at all times. Further, to properly correlate the test results with the different blood samples tested, as well as to be able to selectively route the specimen containers through the instrument system so that only those processes requested are actually performed on a given sample, it is desirable to provide some means for identifying each sample container as it moves through the automated system.
To maintain specimen containers of various sizes in an upright orientation while transiting an automated instrument system, it is common to support each container in a specimen carrier, sometimes referred to as a xe2x80x9cpuck.xe2x80x9d The specimen carrier, which is adapted to receive and retain containers of different diameters and lengths, is designed to interact with the elements of the conveyor system in assuring that each specimen container supported by the carrier is properly routed. To keep track of each of many biological specimen containers transported by an automated system of the above type, it is common to affix a barcode label to each container and to position barcode readers at strategic fixed locations along the conveyor path to read such labels. Each barcode label provides, for example, encoded patient identification data, test types to be performed, and all other information required to assure that the specimen is properly processed and routed through the automated system. The respective outputs of the barcode readers are suitably processed by a computer-based laboratory information system to relate the information on the labels with the processing to be performed. Automated blood analyzing systems of this type are disclosed, for example, in U.S. Pat. No. 5,623,415 and in the published Canadian Patent Application No. 2,216,052, laid open on Mar. 19, 1998.
In the above-noted Canadian Patent Application, an automated transport system is disclosed for transporting biospecimens (e.g., blood and urine) to different test sites. In this system, each biospecimen container (a test tube or vial) is received and transported in a carrier that functions to assure that its respective container is supported in an upright or vertical orientation so that its mouth can be centered relative to an aspiration probe or needle used to extract sample from the container. Each carrier comprises a cylindrically shaped base from which at least three container-retaining members extend upwardly. The retaining members, which are preferably made of heavy gauge stainless steel wire, are equally spaced about the perimeter of the base, and together they define, with the top of the base, a container reception site. Preferably, each of the retainer members is relatively narrow or slender in shape (compared to the surface area of the retained container) so as not to obscure a major portion of a barcode label carried by a container. One end of each retainer member is mechanically latched to the base member by inserting it into a notch in the base and rotating it to position an intermediate portion into an arcuate groove. The respective opposite ends (i.e., the free ends) of the retainer members are biased towards the central axis of the container-reception site so that, collectively, they can receive and retain specimen containers of different diameters. In the preferred embodiment, an O-ring surrounding the free ends of the three retainer members is used to provide the biasing feature. Also disclosed in this application is the use of a programmable magnetic identification system, including a magnetic identification device embedded in the carrier base and read by an appropriate reader to uniquely identify a specimen carrier. This carrier identification scheme is used in conjunction with, or instead of, the indicia carried by the specimen container.
While container carriers of the type disclosed in the above Canadian application might prove useful in transporting specimen containers in an automated transport system, these containers are disadvantageous from the standpoints of manufacturing cost and complexity. For example, the procedure for connecting the retainer members to the base member is labor-intensive and ideally should be avoided. Further, the suggested magnetic identification system, while plausible, is disadvantageous in that it can be readily corrupted, and even erased, by any significant field-generating stimuli in or near the conveyor system; thus, care must be exercised in the system design to provide proper shielding to prevent any magnetic structure in the area from interfering with the magnetic circuit between the carrier""s embedded magnetic tag and the magnetic reader. Further, in a magnetic system, it is difficult to control the extent of the reader""s magnetic interrogation field, thereby making it difficult to unambiguously differentiate adjacent carriers on the conveyor.
Recently, radio-frequency (RF) identification tags in the form of small disks have been used for identification and tracking purposes. Such tags have been used primarily for identifying and tracking animals in which they have been implanted. Each tag is pre-programmed with a unique identification code and/or other information of specific interest that can be read-out as the animal enters an RF field produced by the loop antenna of an RF transceiver or reader. The energy from the transceiver acts to energize the RF tag, thereby enabling the tag to transmit its identification code and any other information of interest, including information that has been written to the tag while in use. The transceiver is adapted to read the identification code over a relatively large range and provide an appropriate output signal. Such RF identification systems are commercially available, e.g., from Intersoft, Estill Springs, Tenn. Owing to the relatively large interrogation fields associated with such systems, they would be impractical for use in a miniaturized specimen conveyor system of the type described above. More particularly, the RF interrogation field is so extensive that it would simultaneously energize multiple tags, making it difficult to selectively detect a single specimen among many other closely spaced specimens. Moreover, due to the large loop area of the antennas used in such RF systems, large electromagnetic and electrostatic fields are produced which may affect devices outside the localized environments. These large antennas are also susceptible to external noise typically present in the medical environment.
In view of the foregoing discussion, an object of this invention is to provide an improved container carrier of the above type, a container carrier that is improved from the standpoint that it is less labor-intensive and costly to fabricate.
Another object of this invention is to provide an improved container carrier of the above type, one that carries an identification tag that is not as corruptible as the magnetic identification scheme proposed by the aforementioned prior art.
Yet another object of this invention is to provide an improved method and apparatus for identifying objects, such as the specimen carriers of the invention, moving together on a conveyor.
According to a preferred embodiment of the invention, a specimen carrier comprises a unitary structure for receiving and retaining a specimen container in an upright orientation. Such unitary structure is defined by a pedestal having upper and lower platforms connected by a stem. Extending upwardly from the upper platform is a plurality of rigid members equally spaced from a central axis passing through the platforms. Extending angularly downward from a free end of each rigid member, toward such central axis, is a flexible finger adapted to engage and press upon the side wall of a container received by the carrier. Collectively, the flexible fingers carried by the rigid members define a container site for receiving and retaining specimen containers of different diameters. Preferably, the unitary structure is made of a moldable thermoplastic chosen for its flexural properties.
According to another aspect of the invention, the specimen carrier of the invention has a chamber formed therein that houses a programmable radio-frequency (RF) identification tag in the form of an RF transponder. Upon being energized by a suitable RF field provided by a specialized RF antenna positioned adjacent the carrier""s intended path of movement, the tag transmits a unique identification code, such code being received by such antenna and decoded by its associated RF reader.
According to another aspect of this invention, a new and improved method for identifying objects moving in an automated conveyor system is provided. Such method comprises the steps of coupling a programmable radio-frequency (RF) identification tag in the form of an RF transponder to the object, such RF transponder being selectively energizable by RF electromagnetic energy to transmit a unique identification code that differentiates that object from other objects; and transmitting RF electromagnetic energy from a location proximate the path and at an energy level adapted to selectively energize only one identification tag coupled to an object moving along the path.
As a result of the invention, the manufacturing costs of container-carriers of the type described are significantly reduced, and an unambiguous identification of the carrier, or any other information carried by the carrier""s RF tag is provided.
The invention and its advantages will be better understood from the ensuing detailed description of a preferred embodiment, reference being made to the accompanying drawings.